Chemotherapy-Induced Posterior Reversible Encephalopathy Syndrome in Childhood Chronic Myeloid Leukemia

Abstract

Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiological phenomenon seen in a wide spectrum of clinical conditions and is characterized clinically by headache, altered mental status, visual loss and seizures and reversible neuroimaging findings. This study evaluated MR imaging in PRES in a clinical oncology setting. MR findings may be helpful in disclosing the underlying pathophysiological mechanisms of the syndrome. The MR imaging protocol consisted of T2-weighted, fluid attenuation inversion recovery (FLAIR), diffusion weighting imaging (DWI) and apparent diffusion coefficient (ADC) sequences. Contrast enhanced computed tomography (CT) of the brain revealed bilateral symmetric subcortical hypodense lesions in the parieto-occipital regions. T2-weighted and FLAIR sequences showed bilateral, symmetrical focal cortical and subcortical hyperintensities involving the parietal and occipital lobes. These areas appeared hyperintense on DWI while the ADC (Apparent Diffusion Coefficient) maps demonstrated higher apparent diffusion coefficients in areas of FLAIR abnormalities thus confirming vasogenic edema. Follow-up scan five days later showed improvement or resolution of the abnormalities. Transient DWI hyperintensities seen in cortical watershed areas corresponding to the hyperintense foci in FLAIR imaging are suggestive of foci of vasogenic edema secondary to vasospasm in highly ischemia-sensitive cerebral tissue.